Technical Science - Term 2 - Week 8

An electrical circuit is a closed loop that allows current to flow. The main components of a circuit include a power source (like a battery), conductors (wires), and loads (devices that use electricity, such as bulbs). Understanding how these components work together is crucial for analyzing and designing circuits.

There are two primary types of circuits: series and parallel. In a series circuit, components are connected end-to-end, meaning the same current flows through all components. In contrast, a parallel circuit has components connected across common points, allowing multiple paths for current. This distinction affects how voltage and current behave in each type.

Ohm's Law is a fundamental principle in electronics that states the relationship between voltage (V), current (I), and resistance (R) in a circuit. It can be expressed with the formula V = I × R. This law allows us to calculate one of these values if the other two are known, making it essential for circuit analysis.

Consider a series circuit with a 12V battery and two resistors of 4Ω and 6Ω. To find the total resistance (R_total), we add the resistances: R_total = 4Ω + 6Ω = 10Ω. Using Ohm's Law, we can find the current (I) flowing through the circuit: I = V / R_total = 12V / 10Ω = 1.2A.

In a parallel circuit with a 12V battery and two resistors of 4Ω and 6Ω, the total resistance (R_total) can be calculated using the formula 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/4 + 1/6, which simplifies to R_total = 2.4Ω. The current through the circuit can then be calculated using Ohm's Law.

Let's work through a problem together. We have a series circuit with a 9V battery and two resistors: 3Ω and 5Ω. First, calculate the total resistance: R_total = 3Ω + 5Ω = 8Ω. Now, apply Ohm's Law to find the current: I = V / R_total = 9V / 8Ω. What is the current flowing through the circuit?

Now it's your turn! Solve the following problems independently: 1) A circuit has a 24V battery and two resistors in series: 10Ω and 15Ω. Calculate the current. 2) In a parallel circuit with a 12V battery and resistors of 6Ω and 12Ω, find the total current flowing from the battery. Show your calculations.

• Volts
• Amperes
• Ohms
• Watts

Answer: Ohms

Resistance is measured in Ohms, which quantifies how much a material opposes the flow of electric current.

• The same through all components
• Different in each component
• Zero
• Only flows through one component

Answer: The same through all components

In a series circuit, the same current flows through each component, as there is only one path for the current to take.

• It increases
• It decreases
• It stays the same
• It becomes infinite

Answer: It decreases

Adding more resistors in parallel provides additional pathways for current, which decreases the overall resistance.

Answer: V = I × R

Ohm's Law states that voltage (V) is equal to the current (I) multiplied by the resistance (R).

Answer: 3A

Using Ohm's Law, I = V / R = 15V / 5Ω = 3A.

• Resistor
• Capacitor
• Inductor
• Transistor

Answer: Capacitor

A capacitor is used to store electrical energy in an electric field.

• The same
• Different
• Zero
• Only across the first component

Answer: The same

In a parallel circuit, each component experiences the same voltage as the power source.